Virtual Biopsy and 3DPan Fusion Imaging for Breast Core Biopsy
Different diagnostic imaging technologies, consolidated and emerging, can nowadays be applied to breast district: Mammography , Breast Tomosynthesis , Ductography , Magnetic Resonance Imaging (MRI) dedicated to breast , Automated Breast Ultrasound Systems (ABUS) with the patient in supine  or prone position  and Molecular Breast Imaging (MBI) .
Free-hand Ultrasound (US) plays an important role in breast diagnostics as a real-time examination, not ionizing and non-invasive, cost effective, ideal also for repetitive followup and able to give information about anatomy (B-Mode modality), hemodynamics (Color, Power and Pulsed Wave Doppler) [8, 9] and tissue stiffness (Elastosonography ). Once a suspected finding is detected in a breast, core biopsy represents a valid alternative to open surgical biopsy in order to remove the suspicious tissue . Only some of the above mentioned imaging technologies are able to offer a guide (direct or indirect; real-time or as a post guiding tool) for core biopsies. The mostly used imaging technologies for breast biopsy guidance are the stereotactic(based on X-Ray)and the US . Also the MRI can be used .
The stereotactic biopsy enables the visualization of the breast micro-calcifications (invisible to the US except when using particular technologies not well diffused or clinically validated as the twinkling artifact [14, 15](Fig. 1), and it represents the perfect choice for core biopsies related to the sampling of this kind of breast findings.
Anyway, the stereotactic breast core biopsy has limitations: it’s not a real-time imaging biopsy procedure and it needs multiple scanning views, with the consequent increase of the ionizing radiation dose to the patient. Moreover, the stereotactic table makes the axilla region not to be imaged and therefore no biopsy guidance is possible in this body area. On the contrary, free hand US has the possibility to image also the axilla area and to guide biopsies in that area .
As per the design of the stereotactic table, some ergonomic problems can arise depending on the particular patient’s conformation and the general health conditions . MRI guided core biopsy is increasing due to raised availability of breast MRI systems. The advantages, with respect to US, are especially related to the high quality anatomical details provided and the large field of view (covering also both breasts at the same time). However, the MRI biopsy guidance procedures are not real-time but they are time consuming and more expensive than the US and not ergonomically optimized; in practice they are executed only when the lesion is not visible with other imaging modalities . Moreover, the lesions near the chest wall, high in the axilla, or those located in the distal breast region may be better guided by US, with respect to MRI .
The present work describes the innovative 3D Panoramic (3DPan) tool of Virtual Navigator technology for the real-time fusion imaging of breast 3D US volumes with bi-dimensional (2D) US scans. This tool was used for the planning and execution of core biopsies in vivo. Furthermore, the procedure was enhanced by a Motion Compensation (MC) technique, using a Motion Control Sensor (MCS), which corrected possible subject’s voluntary, or involuntary (e.g. respiratory) movements, for patient’s and sonographer’s increased comfort and easier US scanning. Additional tests regarding 3DPan imaging capabilities, their practical use and usefulness for core biopsy guidance in ex-vivo will be presented as well.